Safety-bolt



(N Model.)

P. BURNS. 2 SAFETY BOLT.

No. 521,458. Patented June 19, 1894.

E r...r'.'.

l UNITED STATES PATENT OFFICE.

PHILIP BURNS, OF NORWICH, CONNECTICUT'.

SAFETY-BOLT.

SPECIFICATION forming part of Letters Patent No. 521,458, dated June 19, 1894.

`Application filed January 8,1894. Serial No. 496,114. (No model.) I

o all whom it may concern.' y Y Be 1t known that I, PHILIP BURNS, a citizen of the United States, residing at Norwich, in

the county of New London and State of Connecticut, have invented certain new and useful Improvements in Safety-Bolts, which improvements are fully set forth and described V in the following specification, reference being the knob-latch case through which the bolt of said latch projects.

In order to clearly explain said invention I have provided the annexed drawings, in which- Figure 1 is an elevation of a door, and its casing, fitted with my improved safety-bolt. Fig. 2 is a view of theinner face of the door casing showing the strike-plate with my safety-bolt, and its operating slide, located in the rear thereof. Fig. 3 is a cross-sectional view of said casing and of a portion of the door, showing the relative positions of the ordinary knob-latch, located in said door, and of my safety-bolt located in the door casing. Figs. LLand 5 are end and side views of said safetybolt, its housing and operating slide, showing also in dotted lines the strike-plate. Fig. 6 is a central, longitudinal, sectional view of the case of the knob-latch and of the housing of mySafety-bolt showing the latter thrown back and the latch in use, and Fig. 7 is a similar view withthe knob-latch withdrawn and my safety-bolt in use. Fig. 8 is aside view, partly insection, of said safety-bolt, its housing and slide, showing the bolt as madehollow to vreceive its actuating spring and -thus shorten the complete device. Fig. 9 shows end and side views of the housing of my bolt and Fig.

l0 illustrates the slide-plate by face and sidel views. Fig. Y11 illustrates the bolt proper of my device, detached from the other parts.

In the drawings the letter a denotes a door and b its casing or jamb.

c indicates the bolt of a knob-latch of ordinary construction and d an ordinary strikeplate adapted to receive the said knob-latch bolt.

In applying a safety-bolt of my new form I irst remove the strike-plate and borea hole, immediately in line with the opening of said plate, sufficiently large to receive a cylindrical shell e which forms the housing of my safety-bolt proper. One end of said housing is closed, as at e and the opposite end is formed with anenlarged, square, head e2, of plate form, whose sides are turned to provide ways e3 in which a plate f may easily slide.

g indicates the bolt proper of my device` its inner end being squared and its outer or operative end being cut away, as at g. The sides 'of said bolt are also cut to form inclined,

or cam, ways 9v2 whose pitch is equal to the desired endwise movement of said bolt. Plate f, which I have already referred to, is partly cut away, as at f its inner ends being adapted to straddle the projecting end of bolt g and ride upon the inclined ways or surfaces@2 (see Fig. 4). As said slide f is drawn outward the end of bolt gis allowed to project outward through the strike-plate d (see Fig. 7), said bolt being actuated by a spiral, or other suitable, spring h located between its inner end and the bottom of the opening in the housing e, as seen in Figs. 6 and 8; the latter named figure showing the bolt as made hollow to inclose said spring and thus make it possible to use a shorter housing than when the spring abuts the end of-bolt g, as in Fig. 6.

When slide f is forced inward (see Fig. 6) its forked end, riding upon the cam surfaces g2, forces bolt g back into the housing e and, when the slide is in this position, its opening f iscoincident with the bolt c of the knoblatch (assuming of course that the door is closed) and said bolt c may then pass forward into the strike-plate and operate to hold the door precisely as if my safetydevice were not applied. Under ordinary conditions the slide f is pushed inward and the safetyfbolt g thus kept Within its housing, as seen in Fig. 7, when the knob-latch alone can be used but, should it be desired to bring my safety-lock into use, as at night, it is only necessary to draw out the slidefas in full lines in Fig. 7, when spring 7L immediately forces bolt g ont ward and the projecting end of said bolt enters the opening in the case of the knob-latch, eectually locking the door in its closed po sition. It will thus be seen that, while the knob-latch bolt c may ordinarily co-act with its strike-plate, just as elfectually as before my safety-bolt was applied, said safety bolt may with equal ease be brought into service to act as a positive lock that cannot be reached from the outside of the door.

The exposed edge of theslide fprojects laterally, as atfz, so that a inger, or linger nail, may be conveniently used in drawing said slide outward and the forked inner end of said slide is turned outward, as at f3, forming angular projections that are flush with the exposed face of the strikeplate and which serve as stops that may engage said strike-plate to limit the outward movement of the slide (see Figs. 2,4 and 7). These angular ends fsalso serve when the slide is drawn outward, to engage and force back into its case, the bolt c (see Fig. '7). The said slide thus acts to move the opposing bolts c and g out of the way of each other; that is to say,when drawn outward said slide forces the knob-latch bolt c back into its case and permits the safety-bolt g to 'shoot outward and into said case, to lock the door in its closed position and,per contra, when said slide is pushed inward, it forces the safety-bolt g back into its housing and permits theknob-latch boltc to shoot forward into the strike-plate, to operate precisely as if. my safety device were not attached to the door j amb.

lVhen my device is properly applied only the endf2 of the slide can be seen and this, lying close to the door jamb, would hardly be noticed. My complete device is extremely simple, may be cheaply produced and easily applied to either new or old doors.

IIaving described my invention, I claim- 1. In combination with a knob-latch and its strike-plate, a safety-bolt with inclined ways g2 as set forth, located in the rear of said strike-plate and adapted to enter the case of the latch, and a slide-plate intermediate said k nob-latch and safetybolt; said slide bearing upon the inclined Ways of the safety-bolt, substantially as and for the purpose specified.

2. In combination with a strike-plate, abolt seated in the rear thereof, a spring that seeks constantly to force said bolt outward, and a movable cam-plate, substantially as set forth, for forcing said bolt inward against the force of said spring.

3. In combination, a knob-latch bolt, a coincident safety-bolt with inclined ways located in the door jamb, as set forth, a strike-plate, a spring in the rear of said safety-bolt and a slide-plate having an opening f and forked ends bearing upon said inclined ways; said slide-plate being formed with up-turned ends that may engage the strike-plate, in the mauner and for the purpose specified.

PHILIP BURNS.

Witnesses:

FRANK H. ALLEN, ALONZO M. LUTHER. 

